Boto3 ec2 describe_instances always returns empty

问题

I have a very simple sandbox I'm trying to get to work so I can use it in a bigger application:

ec2_client = boto3.client(
    'ec2',
    aws_access_key_id=ACCESS_KEY,
    aws_secret_access_key=SECRET_KEY)

response = ec2_client.describe_instances()
print(response)

and it results in...

{
  'Reservations': [], 
  'ResponseMetadata': {
    'RequestId': '2c28e8aa-da6d-4ca4-8ea7-f672518cac9f',
    'HTTPStatusCode': 200, 
    'HTTPHeaders': {
      'content-type': 'text/xml;charset=UTF-8', 
      'transfer-encoding': 'chunked', 
      'vary': 'Accept-Encoding', 
      'date': 'Thu, 07 Dec 2017 16:44:30 GMT', 
      'server': 'AmazonEC2'
  }, 
  'RetryAttempts': 0}
}

But the problem is no matter how many times I run this Reservations is ALWAYS empty :(.

In AWS consonle I can CLEARLLY see an instance is running...

I tried starting more instances, restarting the instances I had running. I put my initial script in a loop and ran it on repeat while I did this looking for any sign of the Reservations array actually having data.

I double checked that my aws ACCESS_KEY and SECRET_KEY are both correct and pointing to the correct account. They are.

I have no clue why this is. Its so simple and should be working. I'm new to AWS so any help is appreciated.

回答1:

Seems that you forgot to add the region.

Set the region when creating your client

ec2_client = boto3.client(
  'ec2',
  aws_access_key_id=ACCESS_KEY,
  aws_secret_access_key=SECRET_KEY,
  region_name=REGION_NAME
)

response = ec2_client.describe_instances()
print(response)

If your EC2 instances are in Oregon, you can do region_name='us-west-2'

Hard coding credentials is not recommended. You can configure your profiles using the awscli and then reference it in your code.

session = boto3.Session(profile_name='dev')
# Any clients created from this session will use credentials
# from the [dev] section of ~/.aws/credentials.
ec2_client = session.client('ec2')

You can read more about Boto3 credentials Boto3 Credentials

回答2:

The problem is that somehow boto3 was using a region that my instance was not running in. The solution was to specify the region when initializing the client:

ec2_client = boto3.client(
    'ec2',
    region_name='us-east-2',
    aws_access_key_id=ACCESS_KEY,
    aws_secret_access_key=SECRET_KEY)

All credit to @kichik for telling me where to look!

来源：https://stackoverflow.com/questions/47700089/boto3-ec2-describe-instances-always-returns-empty